Seals are used in various applications to prevent the escape of fluid between adjacent surfaces. Many seals are of one piece construction.
When the surfaces to be sealed are very large, it is sometimes impractical to make the seal as a single piece. In other cases the surfaces to be sealed are on separable parts which must be assembled with the seal in place. In such cases a split or segmented seal has been used to seal between the surfaces.
It is sometimes necessary to attach one man made body to another man made body in outer space. When human beings, or other life forms that require an atmosphere to live, are to be housed in the assembled bodies, a seal must be provided in the area where the bodies ar joined together. The seal holds the gases which make up the atmosphere inside the bodies and prevents their escape into outer space.
Usually the seals at the interface between the bodies or modules are in the shape of large rings. A seal typically includes a metal retainer ring with one or more resilient portions extending concentrically about the metal retainer ring.
The resilient portions of the seal abut the adjacent bodies on each side of the seal. The seal is held in place between flange portions on the bodies. When the seal is compressed between the flange portions, the escape of gases from the area beyond the seal is minimized.
The seals between modules of a space craft often must have very large diameters to provide access for people and equipment. Because of size, it is usually impractical to make the seal and retainers as a single piece. In the past, seals have been made in sections. U.S. Pat. No. 3,175,832 discloses an example of a seal made in sections. However, when seals intended for outer space applications are made in sections, certain problems must be overcome.
When a large seal is made in sections, the elastomeric sealing portions of the seal, as well as the retainer, are made in segments. In the past, the resilient portions have been made to extend slightly beyond the edges of the retainer segments prior to assembly of the seal. When the segments are assembled, the resilient portions must be compressed in the areas where they abut one another. Such compression is desirable to minimize leakage. Also when the seal is formed in sections, the holes in the retainer which accept dowels and fasteners used to position and hold the seal, must be positioned precisely to insure that the segments fit together properly.
Problems may arise when a seal suitable for use in outer space applications is made in segments. If the edges of the retainer are not made precisely to provide a tight fit, the effectiveness of the seal joint may be impaired. The resilient sealing portions also have a tendency to curl at the interface between the segments rather than compress one another purely in the tangential direction. Such deformation may also have an adverse impact on seal effectiveness. Of course the necessity of achieving a precise fit requires holding close tolerances which adds difficulty to the manufacture of the seal assembly. Segmented seal assemblies of the type known in the prior art can also be very difficult to assemble particularly in an outer space environment where astronauts have difficulty forcing slight interference fits together or in earth environments where robotic equipment is used to assemble the seal segments.
Thus there exists a need for an interlocking segmented seal that is reliable, less difficult to manufacture and which can be assembled more easily, particularly in outer space environments.